Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
explānātor, ōris, m. [explano], an explainer, interpreter: sunt enim explanatores, ut grammatici poëtarum, Cic. Div. 1, 51, 116: explanator aut interpres ejus legis, Lact. (Cic. ap. Lact.?) 6, 8.